Process for the preparation of polypropylenes from waste plastic feedstocks

ABSTRACT

The present invention relates to a process for the production of propylene-based polymers from waste plastics feedstocks comprising the steps in this order of: (a) providing a hydrocarbon stream A obtained by hydrotreatment of a pyrolysis oil produced from a waste plastics feedstock; (b) optionally providing a hydrocarbon stream B; (c) supplying a feed C comprising a fraction of the hydrocarbon stream A and optionally a fraction of the hydrocarbon stream B to a thermal cracker furnace comprising cracking coil(s); (d) performing a thermal cracking operation in the presence of steam to obtain a cracked hydrocarbon stream D; (e) supplying the cracked hydrocarbon stream D to a separation unit; (f) performing a separation operation in the separation unit to obtain a product stream E comprising propylene; (g) supplying the product stream E to a polymerisation reactor; and (h) performing a polymerisation reaction in the polymerisation reactor to obtain an propylene-based polymer; wherein in step (d): • the coil outlet temperature is ≥800 and ≤850° C., preferably ≥805 and ≤835° C.; and • the weight ratio of steam to feed C is &gt;0.3 and &lt;0.8.

The present invention relates to a process for the preparation ofpolypropylenes from products originating from waste plastic feedstocks.In particular, the invention relates to production of polypropylene fromproducts originating from waste plastic feedstocks with improved carbonefficiency towards polypropylene.

Presently, the disposal of plastic materials as a waste poses anincreasing environmental issue. With increase of global population, andincrease of use of plastic materials per capita, the quantity of plasticmaterial that results as a waste, whether from industrial use or fromconsumer use, reaches such levels that far-reaching innovations inmethods of disposal are rapidly becoming essential. In particular, it isvery much desirable that such innovations also contribute to reductionof detrimental environmental issues, such as fossil carbon utilisationand carbon emissions into the atmosphere.

In many cases, at present, waste plastics are processed by incineration,leading to atmospheric carbon emissions, discarded in landfills, or evenlittered onto land and sea. Such undesired waste disposal increasinglyfaces societal objections. It is therefore an object of development inindustry to find means of processing such waste plastics in a wayovercoming the above objections.

One means of achieving such is via processing the waste plastics viachemical conversion processes into a feed material that again can findits way to the renewed production of plastics. Not only would such routeallow for the re-use of a waste, with the problems associated to it aspresented above, but also could it serve as a replacement ofconventional feed materials that are used in the production of plastics.

A particular route for production of plastics, currently by and far themost widespread route, is via first processing of fossil oil or gasderivatives into building blocks for plastics, and further convertingthese building blocks into plastics via polymerisation processes. Atypical example of such involves the preparation of such buildingblocks, also referred to as monomers, via steam cracking of fossil oilderivatives of the naphtha range. Such monomers include particularlylower mono- and diolefinic compounds, such as ethylene and propylene,next to other valuable chemical building blocks such as aromatics andoxygenated products. These olefinic compounds are on very large scalepolymerised into polyolefin materials, particularly polyethylene andpolypropylene materials.

As the production of polyethylenes and polypropylenes according to theabove route represents a majority part of the global plasticsproduction, and production capacity continues to grow annually, thisroute would be particularly suitable for utilisation of waste plasticsbased feed streams to be converted into new polymeric materials. Suchroute would allow for providing a means to convert plastics to plastics,which is also referred to as circular plastics processing.

In order to be able to process waste plastics as a feed material forsteam cracking operations, it has to be provided as a feed to the steamcracker in such way that the cracking process can be operated at thehighest of efficiencies, and under sustainable conditions.

In this context, with high cracking efficiency it is meant that thecracking is performed under conditions leading to a maximised productionof propylene as part of the product spectrum that is produced in thesteam cracker. Steam cracking involves subjecting a feed stream ofhydrocarbons of mixed chemical structure to a high temperature, underhigh flow velocities, for a certain time. As a result of theseconditions, thermal degradation of the chemical compounds in the feedstream occurs, leading to a certain spectrum of desired chemicalcompounds that find their way into commercial use, either directly orvia further chemical conversion processes. Propylene typically is one ofthe products that is part of the products that forms part of the productcomposition that is formed in such steam cracking process.

By sustainable conditions of steam cracking in the context of thepresent invention is meant that the steam cracking occurs under suchconditions of process and feed stream composition that the run durationof the cracking process, which in commercial operation is a continuousprocess, is as long as possible, before formation of coke or fouling dueto contaminants and/or operational conditions that settles on the insideof the tubes which typically are employed in steam crackers as per thepresent art forces operations to be ceased and reactor tubes to becleaned. This run duration is very much dependent on the composition ofthe feed material and the conditions of cracking, and is desirably aslong as possible to enable an economic operation of the plant.

The propylene that is obtained as part of the product compositionemerging from the steam cracking process is, upon being subjected to aseparation step to isolate it to a desired degree of purity, thenconverted to polypropylene products via a polymerisation process.

It is now an object of the present invention to provide a process thatallows for the production of polypropylene utilising a maximisedefficiency of carbon originating from a waste plastics stream.

According to the present invention, that is now achieved by a processfor the production of propylene-based polymers from waste plasticsfeedstocks comprising the steps in this order of:

-   -   (a) providing a hydrocarbon stream A obtained by hydrotreatment        of a pyrolysis oil produced from a waste plastics feedstock;    -   (b) optionally providing a hydrocarbon stream B;    -   (c) supplying a feed C comprising a fraction of the hydrocarbon        stream A and optionally a fraction of the hydrocarbon stream B        to a thermal cracker furnace comprising cracking coil(s);    -   (d) performing a thermal cracking operation in the presence of        steam to obtain a cracked hydrocarbon stream D;    -   (e) supplying the cracked hydrocarbon stream D to a separation        unit;    -   (f) performing a separation operation in the separation unit to        obtain a product stream E comprising propylene;    -   (g) supplying the product stream E to a polymerisation reactor;        and    -   (h) performing a polymerisation reaction in the polymerisation        reactor to obtain an propylene-based polymer;    -   wherein in step (d):        -   the coil outlet temperature is ≥800 and ≤850° C., preferably            ≥805 and ≤835° C.; and        -   the weight ratio of steam to feed C is >0.3 and <0.8.

The process of the present invention allows for optimisation of thequantity of waste plastic material that finds its way back into apolypropylene that is produced as outcome of the process. The higherthat quantity is, i.e. the higher the quantity of chemical buildingblocks that are present in the waste plastic material that are convertedto the produced polypropylene, the better the sustainability footprintof the process is. The process allows for circular utilisation ofplastics. In addition, the process allows for increased efficiency inthe production of polypropylene in that the fraction of propylene in thecracked hydrocarbon stream D is increased. A further advantage of theprocess of the present invention is that the overall energy consumptiontowards polypropylene is reduced.

In the context of the present invention, polypropylenes are alsoreferred to as propylene-based polymers, which terms are usedinterchangeably. Polypropylenes or propylene-based polymers inaccordance with the present invention may for example be understood tobe polymers comprising >50 wt % of monomeric units that are derived frompropylene, preferably >60 wt %, more preferably >70 wt %, even morepreferably >80 wt %, yet even more preferably >90 wt %, with regard tothe weight of the polymer.

The weight ratio of steam to feed C may for example be >0.35 and <0.8,preferably >0.35 and <0.75, more preferably >0.40 and <0.70.

The process of the present invention allows for the conversion of thewaste plastics material into a polypropylene product.

The waste plastics feedstock that is used for the production of thehydrocarbon stream A of the present process may for example comprisepolyolefins, polyesters, thermoplastic elastomers, polyvinyl chlorides,polystyrenes, or polycarbonates.

Waste plastic feedstocks that may be used for the production of thehydrocarbon stream A can be mixtures comprising polyolefins, polyesters,thermoplastic elastomers, polyvinyl chlorides, polystyrenes, orpolycarbonates. In particular, the waste plastic feedstock that may beused for the production of the hydrocarbon stream A can be mixturescomprising >25.0 wt % of polyolefins, with regard to the total weight ofthe waste plastic feedstock. Preferably, the waste plastic feedstock maycomprise >40.0 wt % of polyolefins, more preferably >50.0 wt %, evenmore preferably >60.0 wt %, or >70.0 wt %. The waste plastic feedstockmay comprise a fraction of non-thermoplastics materials. Suchnon-thermoplastic materials may for example be hydrocarbon-basedmaterials, such as rubber materials, but may also be materials includingpaper, sand and soil. It is an advantage of the present invention thatwaste plastics feedstocks containing up to 10 wt %, preferably up to 5.0wt %, more preferably up to 2.0 wt %, of materials selected from paper,sand and soil, and combinations thereof, may be used in a process forpreparation of polypropylene. This allows for the processing of suchfeedstocks without the need for cleaning processes that may require useof solvents or detergents.

For example, the waste plastics feedstock may comprise ≤10.0 wt % ofingredients being the sum of the content of glass, paper, metal,cardboard, compostable waste, wood, stone, textiles, rubber materialsand superabsorbent hygiene products, with regard to the total weight ofthe waste plastics feedstock.

The waste plastics feedstock may for example comprise ≥90.0 wt % ofpolymeric material, with regard to the total weight of the wasteplastics feedstock.

The waste plastics feedstock may for example comprise a quantity ofpolyesters. For example, the waste plastics feedstock may comprise <20.0wt % of polyesters, preferably <15.0 wt %, more preferably <10.0 wt %,even more preferably <5.0 wt %, even further preferably <2.0 wt %. Thewaste plastics feedstock may in certain embodiments be free frompolyesters.

A particular type of polyester that typically can be present in wasteplastic feedstocks such as employed in the preparation of thehydrocarbon stream A as used in the present process is polyethyleneterephthalate, which may also be referred to as PET. The waste plasticsfeedstock may for example comprise a quantity of PET. For example, thewaste plastics feedstock may comprise <20.0 wt % of PET, preferably<15.0 wt %, more preferably <10.0 wt %, even more preferably <5.0 wt %,even further preferably <2.0 wt %. The waste plastics feedstock may incertain embodiments be free from PET.

Polyesters such as PET contain oxygen atoms in their polymeric chains.The presence of compounds comprising oxygen atoms in the hydrocarbonstream A is subject to certain limitation, since an excess quantity ofoxygen atoms in the compounds that are supplied to the thermal crackerfurnace may lead to problems including fouling and corrosion in thedown-stream processing of the cracked hydrocarbon stream D exiting fromthe thermal cracker furnace. Accordingly, there is a desire to controlor even minimise the quantity of oxygen-containing polymers in the wasteplastics feedstock that is used to prepare the hydrocarbon stream A.

The waste plastics feedstock may for example comprise a quantity ofpolyamides. For example, the waste plastics feedstock may comprise <20.0wt % of polyamides, preferably <15.0 wt %, more preferably <10.0 wt %,even more preferably <5.0 wt %, even further preferably <2.0 wt %. Thewaste plastics feedstock may in certain embodiments be free frompolyamides.

Particular types of polyamide that typically can be present in wasteplastic feedstocks such as employed in the preparation of thehydrocarbon stream A as used in the present process are polyamide 6 andpolyamide 6,6, which may also be referred to as PA6 and PA66,respectively. The waste plastics feedstock may for example comprise aquantity of PA6 or PA66. For example, the waste plastics feedstock maycomprise <20.0 wt % of total of PA 6 and PA66, preferably <15.0 wt %,more preferably <10.0 wt %, even more preferably <5.0 wt %, even furtherpreferably <2.0 wt %. The waste plastics feedstock may in certainembodiments be free from PA6 and/or PA66.

The waste plastics feedstock may for example comprise a quantity ofpolyvinyl chlorides, which may also be referred to as PVC. For example,the waste plastics feedstock may comprise <5.0 wt % of PVC, preferably<2.0 wt %, more preferably <1.0 wt %, even more preferably <0.5 wt %,even further preferably <0.1 wt %. The waste plastics feedstock may incertain embodiments be free from PVC.

The waste plastics feedstock may for example comprise

-   -   <20.0 wt %, preferably <10.0 wt % of polyesters; and/or    -   <20.0 wt %, preferably <10.0 wt % of polyamides; and/or    -   <2.0 wt %, preferably <1.0 wt % of polyvinyl chloride    -   with regard to the total weight of polymeric material in the        waste plastics feedstock.

The presented percentages of polyesters, polyamides and PVC in the wasteplastics feedstock are to be understood to be percentages by weight ofthe total weight of polymeric material present in the waste plasticsfeedstock.

The waste plastic feedstock may further comprise a quantity of moisture,for example the waste plastics feedstock may contain up to 20.0 wt % ofmoisture, preferably up to 10.0 wt %, more preferably up to 5.0 wt %.

The present process allows for the cracked hydrocarbon stream D tocontain a particularly high fraction of propylene. The higher thefraction of propylene in the cracked product, the better the efficiencyof the process towards polypropylene is.

It is preferred that the hydrocarbon stream A has an initial boilingpoint>25° C. and a final boiling point of <350° C., wherein the initialboiling point and the final boiling point are determined in accordancewith ASTM D86 (2012).

The hydrocarbon stream A may for example have an initial boiling pointof >25° C., preferably of >30° C., more preferably of >35° C., even morepreferably of >40° C. The hydrocarbon stream A may for example have aninitial boiling point of <100° C., preferably <90° C., more preferably<80° C., even more preferably <70° C., or <60° C., or <50° C. Thehydrocarbon stream A may for example have an initial boiling pointof >25° C. and <100° C., preferably >35° C. and <80° C.

The hydrocarbon stream A may for example have a final boiling point of<350° C., preferably of <325° C., more preferably of <300° C., even morepreferably of <275° C., even more preferably of <250° C., or <225° C.,or <200° C. The hydrocarbon stream A may for example have a finalboiling point of >150° C., preferably >175° C., more preferably >200°C., even more preferably >250° C., or >275° C., or >300° C. Thehydrocarbon stream A may for example have a final boiling point of >150°C. and <350° C., preferably>200° C. and <325° C., more preferably >200°C. and <300° C.

The hydrocarbon stream A is a material stream that is obtained bytreatment of a waste plastics feedstock. For example, hydrocarbon streamA may be obtained by processing a waste plastics stream in a pyrolysisunit followed by a hydrogenation treatment of the product obtained fromthe pyrolysis unit.

Such pyrolysis unit may be a continuously operating unit, wherein astream of waste plastics is continuously supplied to the unit and atleast a liquid stream comprising pyrolysis products is continuouslyobtained from the unit. Alternatively, the pyrolysis unit may be abatch-wise operating using wherein a quantity of waste plastics isintroduced into the unit, subjected to pyrolysis conditions, andsubsequently at least a liquid stream comprising pyrolysis products isobtained from the unit.

The pyrolysis process that is performed in the pyrolysis unit may be alow-severity pyrolysis process or a high-severity pyrolysis process. Ina low-severity pyrolysis process, the pyrolysis may be performed at atemperature of ≥250° C. and ≤450° C., preferably ≥275° C. and ≤425° C.,more preferably ≥300° C. and ≤400° C. Alternatively, the pyrolysisprocess may be a high-severity process performed at a temperature of≥450° C. and ≤750° C., preferably ≥500° C. and ≤700° C., more preferably≥550° C. and ≤650° C.

The pyrolysis process may be a catalytic process. In such pyrolysisprocess, for example a quantity of a zeolite catalyst such as a ZSM-5zeolite catalyst may be used. In such pyrolysis process, for example aquantity of spent FCC catalyst may be used. In particular, a compositioncomprising a quantity of ZSM-5 catalyst and a quantity of spent FCCcatalyst may be used. For example, a composition comprising a quantityof ZSM-5 and a quantity of spent FCC catalyst may be used, wherein theweight ratio of the spent FCC catalyst to the ZSM-5 catalyst is between0.5 and 5.0, such as between 1.0 and 3.0.

From the pyrolysis process, a liquid hydrocarbon stream may be obtained.The liquid hydrocarbon stream may for example comprise a quantity ofn-paraffins, a quantity of iso-paraffins, a quantity of olefins, aquantity of naphthenes, and/or a quantity of aromatics. The liquidhydrocarbon stream may for example comprise a quantity of n-paraffins, aquantity of iso-paraffins, a quantity of olefins, a quantity ofnaphthenes, and a quantity of aromatics.

In the context of the present invention, n-paraffins that may be presentin the liquid hydrocarbon stream from the pyrolysis process may forexample include n-alkanes having 3 to 40 carbon atoms. The iso-paraffinsthat may be present in the liquid hydrocarbon stream from the pyrolysisprocess may for example have 3 to 40 carbon atoms. The naphthenes thatmay be present in the liquid hydrocarbon stream from the pyrolysisprocess may for example have 3 to 40 carbon atoms. The aromatics thatmay be present in the liquid hydrocarbon stream from the pyrolysisprocess may for example have 6 to 40 carbon atoms.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≥25.0 and ≤95.0 wt % of n-paraffins, with regard to the totalweight of the liquid hydrocarbon stream from the pyrolysis process.Preferably, the liquid hydrocarbon stream from the pyrolysis processcomprises ≥25.0 and ≤80.0 wt % of n-paraffins, more preferably ≥25.0 and≤70.0 wt %, even more preferably ≥25.0 and ≤50.0 wt %.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≥5.0 and ≤40.0 wt % of iso-paraffins, with regard to the totalweight of the hydrocarbon stream A. Preferably, the liquid hydrocarbonstream from the pyrolysis process comprises ≥5.0 and ≤30.0 wt % ofiso-paraffins, more preferably ≥7.5 wt % and ≤25.0 wt %.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≤50.0 wt % of olefins, with regard to the total weight of theliquid hydrocarbon stream from the pyrolysis process. Preferably, theliquid hydrocarbon stream from the pyrolysis process comprises ≤40.0 wt% of olefins, more preferably ≤35.0 wt %, even more preferably ≤30.0 wt%.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≥5.0 and ≤50.0 wt % of olefins, with regard to the total weightof the liquid hydrocarbon stream from the pyrolysis process. Preferably,the liquid hydrocarbon stream from the pyrolysis process comprises ≥10.0and ≤40.0 wt % of olefins, more preferably ≥15.0 and ≤35.0 wt %.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≥5.0 and ≤20.0 wt % of napththenes, with regard to the totalweight liquid hydrocarbon stream from the pyrolysis process. Preferably,the liquid hydrocarbon stream from the pyrolysis process comprises ≥5.0and ≤15.0 wt % of naphthenes, more preferably ≥7.5 wt % and ≤15.0 wt %.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise ≥5.0 and ≤15.0 wt % of aromatics, with regard to the totalweight liquid hydrocarbon stream from the pyrolysis process. Preferably,the liquid hydrocarbon stream from the pyrolysis process comprises ≥5.0and ≤12.5 wt % of aromatics, more preferably ≥7.5 wt % and ≤12.5 wt %.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise:

-   -   ≥25.0 and ≤95.0 wt %, preferably ≥25.0 and ≤70.0 wt %, more        preferably ≥25.0 and ≤50.0 wt %, of n-paraffins; and/or    -   ≥5.0 and ≤20.0 wt %, preferably ≥5.0 and ≤15.0 wt %, more        preferably ≥7.5 and ≤15.0 wt %, of iso-paraffins; and/or    -   ≥5.0 and ≤50.0 wt %, preferably ≥10.0 and ≤40.0 wt %, more        preferably ≥15.0 and ≤35.0 wt %, of olefins; and/or    -   ≥5.0 and ≤20.0 wt %, preferably ≥5.0 and ≤15.0 wt %, more        preferably ≥7.5 and ≤15.0 wt %, of napthenes; and/or    -   ≥5.0 and ≤15.0 wt %, preferably ≥5.0 and ≤12.5 wt %, more        preferably ≥7.5 and ≤12.5 wt %, of aromatics        with regard to the total weight of the liquid hydrocarbon stream        from the pyrolysis process.

In the context of the present invention, the atomic chlorine content isto be understood to be the total weight of chlorine atoms present inmolecules in the hydrocarbon stream as fraction of the total weight ofthe hydrocarbon stream. Also, the atomic nitrogen content is to beunderstood to be the total weight of nitrogen atoms present in moleculesin the hydrocarbon stream as fraction of the total weight of thehydrocarbon stream.

The liquid hydrocarbon stream from the pyrolysis process may for examplecomprise a certain quantity of contaminants. For example, the liquidhydrocarbon stream from the pyrolysis process may contain a quantity ofcompounds comprising chlorine atoms. The quantity of compoundscomprising chlorine atoms may be expressed as the atomic chlorinecontent of the liquid hydrocarbon stream from the pyrolysis process. Forexample, the liquid hydrocarbon stream from the pyrolysis process mayhave an atomic chlorine content of <800 ppm by weight, as determined inaccordance with ASTM UOP 779-08, preferably <700 ppm, more preferably<600 ppm, even more preferably <500 ppm, even more preferably <400 ppm.

The liquid hydrocarbon stream from the pyrolysis process may comprise aquantity of compounds comprising nitrogen atoms. The quantity ofcompounds comprising nitrogen atoms may be expressed as the atomicnitrogen content of the liquid hydrocarbon stream from the pyrolysisprocess. For example, the liquid hydrocarbon stream from the pyrolysisprocess may have an atomic nitrogen content of <1600 ppm by weight, asdetermined in accordance with ASTM D5762 (2012), preferably <1500 ppm,more preferably <1400 ppm, even more preferably <1300 ppm, even morepreferably <1200 ppm, or <1100 ppm, or <1000 ppm. For example, theliquid hydrocarbon stream from the pyrolysis process may have an atomicnitrogen content of <100 ppm by weight as determined in accordance withASTM D4629 (2017).

The liquid hydrocarbon stream from the pyrolysis process may comprise aquantity of compounds containing olefinic unsaturations. An indicationfor the quantity of olefinic unsaturations is the bromine number of thehydrocarbon stream. The bromine number indicates the quantity of brominein g that reacts with 100 g of the hydrocarbon specimen when testedunder the conditions of ASTM D1159-07 (2012). For example, the liquidhydrocarbon stream from the pyrolysis process as used in the process ofthe present invention may have a bromine number of <100, preferably <95,more preferably <90, even more preferably <85.

The liquid hydrocarbon stream from the pyrolysis process may besubjected to a hydrotreatment process to result in the hydrocarbonstream A that may be supplied to the process for preparation ofpropylene-based polymers according to the present invention. Suchhydrotreatment process may be a process in which the liquid hydrocarbonstream from the pyrolysis process is subjected to hydrogen, such as inthe presence of a catalyst.

The hydrotreatment process may involve hydrogenation, hydrocracking,hydrodearomatisation, hydrodesulfurisation, and hydrodenitrification.The hydrotreatment may be performed in a reactor vessel operated attemperatures of between 200° C. and 500° C. The hydrotreatment may beperformed at a pressure of up to 25 MPa, preferably up to 20 MPa.

The liquid product that is obtained from the hydrotreatment step may besupplied to the process of the invention as hydrocarbon stream A. Thehydrocarbon stream A may for example comprise a quantity of n-paraffins,a quantity of iso-paraffins, a quantity of olefins, a quantity ofnaphthenes, and/or a quantity of aromatics. The liquid hydrocarbonstream may for example comprise a quantity of n-paraffins, a quantity ofiso-paraffins, a quantity of olefins, a quantity of naphthenes, and aquantity of aromatics.

In the context of the present invention, n-paraffins that may be presentin the hydrocarbon stream A may for example include n-alkanes having 3to 40 carbon atoms. The iso-paraffins that may be present in thehydrocarbon stream A may for example have 3 to 40 carbon atoms. Thenaphtenes that may be present in the hydrocarbon stream A may forexample have 3 to 40 carbon atoms. The aromatics that may be present inthe hydrocarbon stream A may for example have 6 to 40 carbon atoms.

The hydrocarbon stream A may for example comprise ≥25.0 and ≤95.0 wt %of n-paraffins, with regard to the total weight of the hydrocarbonstream A. Preferably, the hydrocarbon stream A comprises ≥25.0 and ≤80.0wt % of n-paraffins, more preferably ≥25.0 and ≤70.0 wt %.

The hydrocarbon stream A may for example comprise ≥5.0 and ≤70.0 wt % ofiso-paraffins, with regard to the total weight of the hydrocarbon streamA. Preferably, the hydrocarbon stream A comprises ≥5.0 and ≤50.0 wt % ofiso-paraffins, more preferably ≥7.5 wt % and ≤40.0 wt %.

The hydrocarbon stream A may for example comprise ≤5.0 wt % of olefins,with regard to the total weight of the hydrocarbon stream A. Preferably,the hydrocarbon stream A comprises ≤2.0 wt % of olefins, more preferably≤1.0 wt %.

The hydrocarbon stream A may for example comprise ≥5.0 and ≤20.0 wt % ofnapththenes, with regard to the total weight of the hydrocarbon streamA. Preferably, the hydrocarbon stream A comprises ≥5.0 and ≤15.0 wt % ofnaphthenes, more preferably ≥7.5 wt % and ≤15.0 wt %.

The hydrocarbon stream A may for example comprise ≥5.0 and ≤15.0 wt % ofaromatics, with regard to the total weight of the hydrocarbon stream A.Preferably, the hydrocarbon stream A comprises ≥5.0 and ≤12.5 wt % ofaromatics, more preferably ≥7.5 wt % and ≤12.5 wt %.

The hydrocarbon stream A may for example comprise:

-   -   ≥25.0 and ≤95.0 wt %, preferably ≥25.0 and ≤80.0 wt %, more        preferably ≥25.0 and ≤70.0 wt %, of n-paraffins; and/or    -   ≥5.0 and ≤70.0 wt %, preferably ≥5.0 and ≤50.0 wt %, more        preferably ≥7.5 and ≤40.0 wt %, of iso-paraffins; and/or    -   ≤5.0 wt %, preferably ≤2.0 wt %, more preferably 1.0 wt %, of        olefins; and/or    -   ≥5.0 and ≤20.0 wt %, preferably ≥5.0 and ≤15.0 wt %, more        preferably ≥7.5 and ≤15.0 wt %, of napthenes; and/or    -   ≥5.0 and ≤15.0 wt %, preferably ≥5.0 and ≤12.5 wt %, more        preferably ≥7.5 and ≤12.5 wt %, of aromatics        with regard to the total weight of the hydrocarbon stream A.

The hydrocarbon stream A may for example comprise a certain quantity ofcontaminants. For example, the hydrocarbon stream A may contain aquantity of compounds comprising chlorine atoms. The quantity ofcompounds comprising chlorine atoms may be expressed as the atomicchlorine content of the hydrocarbon stream A. For example, thehydrocarbon stream A may have an atomic chlorine content of <10 ppm byweight, as determined in accordance with ASTM UOP 779-08, preferably <5ppm, more preferably <2 ppm.

The hydrocarbon stream A may comprise a quantity of compounds comprisingnitrogen atoms. The quantity of compounds comprising nitrogen atoms maybe expressed as the atomic nitrogen content of the hydrocarbon stream A.For example, the hydrocarbon stream A may have an atomic nitrogencontent of <50 ppm by as determined in accordance with ASTM D4629(2017), preferably <10 ppm, more preferably <5 ppm, even more preferably<2 ppm.

The hydrocarbon stream A may comprise a quantity of compounds containingolefinic unsaturations. An indication for the quantity of olefinicunsaturations is the bromine number of the hydrocarbon stream. Thebromine number indicates the quantity of bromine in g that reacts with100 g of the hydrocarbon specimen when tested under the conditions ofASTM D1159-07 (2012). For example, the hydrocarbon stream A as used inthe process of the present invention may have a bromine number of <10,preferably <7.5, more preferably <5.0, even more preferably <3.0, evenmore preferably <1.0.

The hydrocarbon stream A may comprise a quantity of compounds containingsulfur. The quantity of compounds containing sulphur may be determinedas the total sulfur content in accordance with ASTM D5453 (2012). Forexample, the hydrocarbon stream A may have a total sulfur content of<500 ppm, preferably <300 ppm, more preferably <100 ppm, even morepreferably <50 ppm.

It has to be understood that all values expressed herein as ppm reflectparts per million by weight.

It is preferred that the hydrocarbon stream B has an initial boilingpoint>25° C. and a final boiling point of <350° C., wherein the initialboiling point and the final boiling point are determined in accordancewith ASTM D86 (2012).

The hydrocarbon stream B may for example have an initial boiling pointof >25° C., preferably of >30° C., more preferably of >35° C., even morepreferably of >40° C. The hydrocarbon stream B may for example have aninitial boiling point of <100° C., preferably <90° C., more preferably<80° C., even more preferably <70° C., or <60° C., or <50° C.

The hydrocarbon stream B may for example have a final boiling point of<350° C., preferably of <325° C., more preferably of <300° C., even morepreferably of <275° C., even more preferably of <250° C., or <225° C.,or <200° C. The hydrocarbon stream B may for example have a finalboiling point of >150° C., preferably >175° C., more preferably >200°C., even more preferably >250° C., or >275° C., or >300° C.

The hydrocarbon stream B may for example comprise ≥25.0 and ≤95.0 wt %of n-paraffins, with regard to the total weight of the hydrocarbonstream B. Preferably, the stream A comprises ≥25.0 and ≤80.0 wt % ofn-paraffins, more preferably ≥25.0 and ≤50.0 wt %.

The hydrocarbon stream B may for example comprise ≥5.0 and ≤40.0 wt % ofiso-paraffins, with regard to the total weight of the hydrocarbon streamB. Preferably, the hydrocarbon stream B comprises ≥5.0 and ≤30.0 wt % ofiso-paraffins, more preferably ≥7.5 wt % and ≤25.0 wt %.

The hydrocarbon stream B may for example comprise ≤2.0 wt % of olefins,with regard to the total weight of the hydrocarbon stream B. Preferably,the hydrocarbon stream B comprises ≤1.5 wt % of olefins, more preferably≤1.0 wt %, even more preferably ≤0.5 wt %.

The hydrocarbon stream B may for example comprise ≥0.01 and ≤2.0 wt % ofolefins, with regard to the total weight of the hydrocarbon stream B.Preferably, the hydrocarbon stream B comprises ≥0.01 and ≤1.5 wt % ofolefins, more preferably ≥0.01 and ≤1.0 wt %.

The hydrocarbon stream B may for example comprise ≥0.5 and ≤50.0 wt % ofnapththenes, with regard to the total weight of the hydrocarbon streamB. Preferably, the hydrocarbon stream B comprises ≥5.0 and ≤40.0 wt % ofnaphthenes, more preferably ≥7.5 wt % and ≤30.0 wt %.

The hydrocarbon stream B may for example comprise ≥0.5 and ≤50.0 wt % ofaromatics, with regard to the total weight of the hydrocarbon stream B.Preferably, the hydrocarbon stream B comprises ≥5.0 and ≤25.0 wt % ofaromatics, more preferably ≥7.5 wt % and ≤20.0 wt %.

The hydrocarbon stream B may for example comprise:

-   -   ≥25.0 and ≤95.0 wt %, preferably ≥25.0 and ≤80.0 wt %, more        preferably ≥25.0 and ≤50.0 wt %, of n-paraffins; and/or    -   ≥5.0 and ≤40.0 wt %, preferably ≥5.0 and ≤30.0 wt %, more        preferably ≥7.5 and ≤25.0 wt %, of iso-paraffins; and/or    -   ≤2.0 wt %, preferably ≥0.01 and ≤1.5 wt %, more preferably ≥0.01        and ≤1.0 wt %, of olefins; and/or    -   ≥0.5 and ≤50.0 wt %, preferably ≥5.0 and ≤40.0 wt %, more        preferably ≥7.5 and ≤30.0 wt %, of napthenes; and/or    -   ≥0.5 and ≤50.0 wt %, preferably ≥5.0 and ≤25.0 wt %, more        preferably ≥7.5 and ≤20.0 wt %, of aromatics        with regard to the total weight of the hydrocarbon stream B.

The fraction of olefins F_(O,C) in the feed C may be calculated as:

F _(O,C) =F _(O,A) *F _(A,C) +F _(O,B) *F _(B,C)

Wherein:

-   -   F_(O,C) is the weight fraction of olefins in feed C, in wt %,        with regard to the total weight of feed C;    -   F_(O,A) is the weight fraction of olefins in the hydrocarbon        stream A, in wt %, with regard to the total weight of        hydrocarbon stream A;    -   F_(O,B) is the weight fraction of olefins in the hydrocarbon        stream B, in wt %, with regard to the total weight of        hydrocarbon stream B;    -   F_(A,C) is the weight fraction of hydrocarbon stream A in feed        C, with regard to the total weight of feed C; and    -   F_(B,C) is the weight fraction of hydrocarbon stream B in feed        C, with regard to the total weight of feed C.

It is preferred that the fraction of olefins F_(O,C) in the feed C is≤2.0, preferably ≤1.8, more preferably ≤1.6, even more preferably ≤1.5wt % with regard to the total weight of feed C.

The feed C that is supplied to the thermal cracker furnace comprises afraction of the hydrocarbon stream A and a fraction of the hydrocarbonstream B.

The feed C may be supplied to the thermal cracker furnace via one ormore inlet(s) wherein the fraction of the hydrocarbon stream A and thehydrocarbon stream B are combined prior to entering the thermal crackingfurnace. Alternatively, the feed C may be supplied to the thermalcracking furnace in such way that the fraction of hydrocarbon stream Aand the fraction of the hydrocarbon stream B enter the furnace viaseparate inlets.

The feed C may for example be a pre-mixed composition comprising afraction of hydrocarbon stream A and a fraction of hydrocarbon stream B,wherein the feed C is supplied to the thermal cracking furnace as a mixvia one or more inlets, or alternatively may be the total quantity ofhydrocarbon stream A and hydrocarbon stream B, wherein the feed C issupplied to the thermal cracking furnace as separate streams of A and B,via one or more inlet(s) for each stream.

In the process of the present invention, the coil outlet temperature(COT) of the steam cracker furnace is ≥800 and ≤870° C., preferably ≥810and ≤870° C., more preferably ≥820 and ≤870° C. Operating the crackerfurnace in this temperature range of COT allows for cracking thefeedstock to a desired product slate, whilst ensuring a sustainable anddurable operation of the cracker furnace.

The feed C may for example comprise a quantity of ≤99.0 wt, or ≤95.0 wt,or ≤90.0 wt % of hydrocarbon stream A, with regard to the total weightof feed C, for example ≤75.0 wt %, for example ≤60.0 wt %, for example≤50.0 wt %, for example ≤40.0 wt %, for example ≤25.0 wt %, for example≤20.0 wt %, for example ≤10.0 wt %. The feed C may for example comprisea quantity of ≥5.0 wt % of hydrocarbon stream A, preferably ≥10.0 wt %,more preferably ≥20.0 wt %, even more preferably ≥30.0 wt %, even morepreferably ≥40.0 wt %, even more preferably ≥50.0 wt %, or ≥70.0 wt %,or ≥90.0 wt %. The feed C may for example comprise a quantity of ≥5.0and ≤99.0 wt % of hydrocarbon stream A, preferably ≥5.0 and ≤95.0 wt %,more preferably ≥5.0 and ≤90.0 wt %, more preferably ≥10.0 and ≤75.0 wt%, more preferably ≥20.0 and ≤60.0 wt %.

In a certain embodiment, the feed C may consist of hydrocarbon stream A.

Such operation of the process of the invention presents as benefit thatis allows for the use of a hydrocarbon stream A that is obtained asliquid stream from hydrotreatment step subsequent to a pyrolysis unit.This allows for the conversion of waste plastics as a certain majorfraction of a feed for a thermal cracking furnace, and therebycontributes to process economics of the conversion of waste plastics tonew virgin polypropylene.

For example, the feed C may for example comprise a quantity of ≥5.0 and≤90.0 wt % of hydrocarbon stream A, preferably ≥10.0 and ≤75.0 wt %,more preferably ≥20.0 and ≤60.0 wt %, or may consist of hydrocarbonstream A, preferably wherein hydrocarbon stream A is obtained as liquidstream from a hydrotreatment unit. In such embodiment, the hydrocarbonstream A may have:

-   -   an atomic chlorine content of <10 ppm by weight as determined in        accordance with ASTM UOP 779-08; and/or    -   an atomic nitrogen content of <50 ppm by weight as determined in        accordance with ASTM D5762 (2012); and/or    -   a bromine number of <10 as determined in accordance with ASTM        D1159-07 (2012); and/or    -   a sulfur content of <500 ppm as determined in accordance with        ASTM D5453 (2012).

After the thermal cracking operation (d) is performed, a crackedhydrocarbon stream D is obtained from the thermal cracking furnace. Thecomposition of the cracked hydrocarbon stream D depends on thecomposition of the feed stream C. Typically, a cracked hydrocarbonstream comprises mono-olefins such as ethylene, propylene, butylenes,di-olefins such as butadiene, and aromatic compounds. In view ofoptimised process utilisation, it is desired that the quantity ofethylene and propylene in the cracked hydrocarbon stream D is high. Thecracked hydrocarbon stream D may for example comprise ≥40.0 wt % of thetotal of ethylene and propylene, with regard to the total weight of thestream D. Preferably, the stream D may comprise ≥45.0 wt % of the totalof ethylene and propylene, more preferably ≥50.0 wt % of the total ofethylene and propylene.

The process of the present invention allows for production of aparticularly high quantity of propylene as part of the crackedhydrocarbon stream D. For example, the quantity of propylene in thestream D may be ≥10.0 wt %, preferably ≥12.5 wt %, more preferably ≥15.0wt %.

Upon exiting the thermal cracking furnace, the cracked hydrocarbonstream D is supplied to a separation unit. In the separation unit, aseparation operation is performed to obtain a product stream Ecomprising propylene.

In certain embodiments, the product stream E may preferablycomprise >50.0 vol %, of propylene, with regard to the total weight ofthe product stream. In such embodiment, the product stream E may forexample comprise ≤50.0 vol % propane. A product stream E of suchcomposition may be used as feed in chemical processes such as in theproduction of cumene.

In certain embodiments, the product stream E may preferablycomprise >94.0 vol %, of propylene, with regard to the total weight ofthe product stream. In such embodiment, the product stream E may forexample comprise ≤6.0 vol % propane. It is preferred that the productstream E comprises ≤2500 ppm by vol. of the total of ethane and methane.A product stream E of such composition may be used as feed in chemicalprocesses such as in the production of acrylonitrile or cumene.

It is preferred that the product stream E comprises ≥95.0 vol %, morepreferably ≥98.0 vol % of propylene, with regard to the total weight ofthe product stream E. It is preferred that the product stream Ecomprises ≤500 ppm by vol. of methane. It is preferred that the productstream E comprises ≤5 ppm by vol. of oxygen. Such high purity isrequired to enable subsequent polymerisation to be performed withoutdisturbance of the polymerisation process. For example, the presence ofan excess of impurities in the product stream E may lead to deactivationof catalyst in catalytic polymerisation processes.

Subsequent to the separation operation (f), the obtained product streamE is supplied to a polymerisation reactor. In such polymerisationreactor, a polymerisation reaction (h) is performed to obtain anpropylene-based polymer.

The polymerisation reaction may be a solution polymerisation reaction, agas-phase polymerisation reaction, or a slurry polymerisation reaction.

The polymerisation reaction of step (h) may be performed using a singlereactor, or alternatively using multiple reactors, such as multiplereactors positioned in series. Each reactor in such arrangementcomprising multiple reactors may individually be a gas-phasepolymerisation reactor, a slurry polymerisation reactor, or a solutionpolymerisation reactor. Each reactor in such arrangement may be suppliedwith different monomeric or polymeric reactants, such as olefins orelastomers, to produce propylene-based homopolymers, copolymers, orpolypropylene-elastomer copolymers.

In a particular embodiment, the polymerisation reaction of step (h) is agas-phase polymerisation process. Such gas-phase polymerisation processmay be performed in the presence of a catalyst system for thepolymerisation of propylene. Such catalyst system may for example be aZiegler-Natta type catalyst system, a single-site type catalyst systemsuch as a metallocene-type catalyst system, or any other catalyst systemknown in the art that is suitable for polymerisation of propylene in agas-phase process.

Such gas-phase polymerisation process may be a homopolymerisationprocess or a copolymerisation process. For example, ethylene, 1-butene,4-methyl-1-pentene, 1-hexene or 1-octene may be used as co-monomers insuch copolymerisation process. When a copolymerisation is performed, forexample a copolymerisation using ethylene as a co-monomer, the overallprocess efficiency in terms of the fraction of carbon atoms originatingfrom the waste plastics feed that are finally converted into thepropylene-based polymer is even more advantageous since the co-monomers,in particular ethylene, may originate as result of the cracking step (d)of the process of the present invention and therefore may also originatefrom the waste plastics feedstock, as a result of which the fractionwaste plastics that is converted to a new polymer is increased, therebycontributing to the overall circularity of the process.

A particular gas-phase polymerisation processes that may be used for thepolymerisation reaction of step (h) of the present invention is afluidised-bed polymerisation process. In such process, the formedpolypropylene particles are maintained in a fluidised state by upwardsflow of the reactant gases, comprising propylene, during the time thatthe reaction takes place, wherein once the particles are concluded tohave reached the desired degree of polymerisation, they are evacuatedfrom the reactor together with the gaseous medium which is subsequentlyseparated from the formed particles and recycled as reactant, togetherwith a make-up stream to compensate the reactant consumption.

Such fluidised-bed process is particularly desirable as it allows forpolymerisation of propylene at relatively moderate levels of energyconsumption, combined with a relatively moderate capital investment thatis required.

Accordingly, use of a fluidised-bed gas-phase polymerisation process forthe polymerisation reaction of step (h) of the present process maycontribute to the overall carbon efficiency of the process of theinvention as a result of the reduced energy requirements.

In certain embodiments of the present invention, the polymerisationreaction in step (h) may for example be:

-   -   I. a gas-phase polymerisation process performed in the presence        of a catalyst system for the polymerisation of propylene;    -   II. a solution polymerisation process performed in the presence        of a catalyst system for the polymerisation of propylene;    -   III. a slurry polymerisation process performed in the presence        of a catalyst system for the polymerisation of propylene; or    -   IV. a process comprising multiple of the processes I through        III.

In a certain embodiment, the invention also relates to a process for theproduction of propylene from waste plastics feedstocks comprising thesteps in this order of:

-   -   (a) providing a hydrocarbon stream A obtained by hydrotreatment        of a pyrolysis oil produced from a waste plastics feedstock;    -   (b) optionally providing a hydrocarbon stream B;    -   (c) supplying a feed C comprising a fraction of the hydrocarbon        stream A and optionally a fraction of the hydrocarbon stream B        to a thermal cracker furnace comprising cracking coil(s);    -   (d) performing a thermal cracking operation in the presence of        steam to obtain a cracked hydrocarbon stream D;    -   (e) supplying the cracked hydrocarbon stream D to a separation        unit; and    -   (f) performing a separation operation in the separation unit to        obtain a product stream E comprising propylene;    -   wherein in step (d):        -   the coil outlet temperature is >800 and <850° C., preferably            ≥805 and ≤835° C.; and        -   the weight ratio of steam to composition C is >0.3 and <0.8.

In such embodiment, hydrocarbon stream A may for example have

-   -   an initial boiling point as determined in accordance with ASTM        D86 (2012) of >25° C.;    -   a final boiling point as determined in accordance with ASTM        D86 (2012) of <350° C.;    -   an atomic chlorine content of <10 ppm by weight as determined in        accordance with ASTM UOP 779-08;    -   an atomic nitrogen content of <50 ppm by weight as determined in        accordance with ASTM D4629 (2017); and/or    -   a bromine number of <10 as determined in accordance with ASTM        D1159-07 (2012); and/or    -   a total sulfur content of <500 ppm as determined in accordance        with ASTM D5453 (2012).

Further in such embodiment, in step (c), the feed C may consist of thehydrocarbon stream A, or may comprise 5.0 and 90.0 wt %, preferably 20.0and 60.0 wt % of hydrocarbon stream A, with regard to the total weightof feed C.

The invention will now be illustrated by the following non-limitingexamples. The presented values for the examples have been obtained bymodeling steam cracking operations of various feedstocks using asmodeling software the Spyro 6.5 package, a commercially availablemodeling software package obtainable from Technip/Pyrotec.

Modeling was performed using feedstocks having the compositions as setout below in table 1.

TABLE 1 Compositions of feedstocks used in modelling via Spyro 6.5. FFHT n-paraffins 30 51 iso-paraffins 32 30 olefins 0 0.7 napthenes 19 8aromatics 19 10

Wherein the percentage as expressed represents a weight percentage ofthe respective fractions with regard to the total weight of thefeedstock.

FF is a conventional fossil feedstock of the naphtha range andcorresponds to hydrocarbon stream B as defined in the current invention.HT is a feed obtained as liquid stream from the hydrotreatment of aliquid stream obtained from the pyrolysis of waste plastics andcorresponds to hydrocarbon stream A as defined in the current invention.

Using the above feedstocks, a number of calculations using the Spyro 6.5package were performed according to the conditions set out below intable 2.

TABLE 2 Conditions for modelling in Spyro 6.5. Experiment Feed COT S/O1A 100% FF 810 0.35 1B 5.0% HT; 95.0% FF 810 0.35 1C 10.0% PY; 90.0% FF810 0.35 1D 100% HT 810 0.35 2A 100% FF 820 0.35 2B 5.0% PY; 95.0% FF820 0.35 2C 10.0% PY; 90.0% FF 820 0.35 2D 100% HT 820 0.35 3A 100% FF840 0.35 3B 5.0% PY; 95.0% FF 840 0.35 3C 10.0% PY; 90.0% FF 840 0.35 3D100% HT 840 0.35 4A 100% FF 860 0.35 4B 5.0% PY; 95.0% FF 860 0.35 4C10.0% PY; 90.0% FF 860 0.35 4D 100% HT 860 0.35

Wherein:

-   -   Feed is the composition of feed C, wherein the percentages are        in wt % of each of the feedstocks with regard to the total        weight of feed C.    -   COT is the coil outlet temperature of the steam cracker furnace,        in ° C.    -   S/O is the weight ratio of steam to feed C.

Using the above conditions, the model calculations provided the productslate of the cracking operations performed for each of the listedexperiments, results of which are presented below.

C3 = Energy Experiment C3 = increase saving 1A 14.14 1B 14.26 0.84%0.26% 1C 14.38 1.70% 0.53% 1D 16.46 16.41% 3.93% 2A 13.60 2B 13.72 0.88%0.31% 2C 13.83 1.70% 0.62% 2D 15.83 16.40% 4.58% 3A 12.17 3B 12.28 0.90%0.37% 3C 12.38 1.72% 0.74% 3D 14.23 16.93% 6.06% 4A 10.34 4B 10.43 0.87%0.44% 4C 10.53 1.83% 0.88% 4D 12.20 17.99% 7.75%

Wherein:

-   -   C3=is the wt % of propylene as part of the cracked hydrocarbon        stream, corresponding to the cracked hydrocarbon stream D as        defined in the present invention.    -   C3=increase is the increase in propylene as part of the cracked        hydrocarbon stream in wt % as compared to the propylene fraction        produced using 100% of feed FF.    -   Energy saving is the reduction of fuel gas consumption in the        cracking operation in GJ per ton of propylene produced,        expressed in %, as compared to the energy consumption using 100%        of feed FF.

As indicated by the results of the cracker modeling above, the processaccording to the present invention allows for the optimization of yieldof polypropylene and reduction of energy to produce the polypropylene,whilst allowing for a circular use of waste plastics given the feedstockbeing based on waste plastics.

1. Process for the production of propylene-based polymers from wasteplastics feedstocks comprising the steps in this order of: (a) providinga hydrocarbon stream A obtained by hydrotreatment of a pyrolysis oilproduced from a waste plastics feedstock; (b) optionally providing ahydrocarbon stream B; (c) supplying a feed C comprising a fraction ofthe hydrocarbon stream A and optionally a fraction of the hydrocarbonstream B to a thermal cracker furnace comprising cracking coil(s); (d)performing a thermal cracking operation in the presence of steam toobtain a cracked hydrocarbon stream D; (e) supplying the crackedhydrocarbon stream D to a separation unit; (f) performing a separationoperation in the separation unit to obtain a product stream E comprisingpropylene; (g) supplying the product stream E to a polymerisationreactor; and (h) performing a polymerisation reaction in thepolymerisation reactor to obtain an propylene-based polymer; wherein instep (d): the coil outlet temperature is ≥800 and ≤850° C.; and theweight ratio of steam to feed C is >0.3 and <0.8.
 2. Process accordingto claim 1, wherein the hydrocarbon stream A has an initial boilingpoint of >25° C. and a final boiling point of <350° C., wherein theinitial boiling point and the final boiling point are determined inaccordance with ASTM D86 (2012).
 3. Process according to claim 1,wherein the hydrocarbon stream A has an atomic chlorine content of <10ppm by weight as determined in accordance with ASTM UOP 779-08. 4.Process according to claim 1, wherein the hydrocarbon stream A has anatomic nitrogen content of <50 ppm by weight as determined in accordancewith ASTM D4629 (2017).
 5. Process according to claim 1 wherein thehydrocarbon stream A has a bromine number of <10 as determined inaccordance with ASTM D1159-07 (2012).
 6. Process according to claim 1wherein the hydrocarbon stream A has a total sulfur content of <500 ppmas determined in accordance with ASTM D5453 (2012).
 7. Process accordingto claim 1, wherein (i) the hydrocarbon stream A comprises: ≥25.0 and≤95.0 wt %, of n-paraffins; and/or ≥5.0 and ≤70.0 wt %, ofiso-paraffins; and/or ≤5.0 wt %, of olefins; and/or ≥5.0 and ≤20.0 wt %,of napthenes; and/or ≥5.0 and ≤15.0 wt %, of aromatics; with regard tothe total weight of the hydrocarbon stream A; and/or (ii) thehydrocarbon stream B comprises: ≥25.0 and ≤95.0 wt %, of n-paraffins;and/or ≥5.0 and ≤40.0 wt %, of iso-paraffins; and/or ≤2.0 wt %, ofolefins; and/or ≥0.5 and ≤50.0 wt %, of napthenes; and/or ≥0.5 and ≤50.0wt %, of aromatics with regard to the total weight of the hydrocarbonstream B.
 8. Process according to claim 1, wherein in step (c), the feedC consists of the hydrocarbon stream A or wherein the feed C comprises≥5.0 and ≤90.0 wt %, of hydrocarbon stream A, with regard to the totalweight of feed C.
 9. Process according to claim 1, wherein the wasteplastics feedstock comprises ≥90.0 wt % of polymeric material, withregard to the total weight of the waste plastics feedstock.
 10. Processaccording to claim 1, wherein the waste plastics feedstock comprises<20.0 wt %, of polyesters; and/or <20.0 wt %, of polyamides; and/or <2.0wt %, of polyvinyl chloride with regard to the total weight of polymericmaterial in the waste plastics feedstock.
 11. Process according to claim1, wherein the waste plastics feedstock comprises ≤10.0 wt % ofingredients being the sum of the content of glass, paper, metal,cardboard, compostable waste, wood, stone, textiles, rubber materialsand superabsorbent hygiene products, with regard to the total weight ofthe waste plastics feedstock.
 12. Process according to claim 1, whereinthe polymerisation is I. a gas-phase polymerisation process performed inthe presence of a catalyst system for the polymerisation of propylene;II. a solution polymerisation process performed in the presence of acatalyst system for the polymerisation of propylene; III. a slurrypolymerisation process performed in the presence of a catalyst systemfor the polymerisation of propylene; or IV. a process comprisingmultiple of the processes I through III.
 13. Process for the productionof propylene from waste plastics feedstocks comprising the steps in anorder of: (a) providing a hydrocarbon stream A obtained byhydrotreatment of a pyrolysis oil produced from a waste plasticsfeedstock; (b) optionally providing a hydrocarbon stream B; (c)supplying a feed C comprising a fraction of the hydrocarbon stream A andoptionally a fraction of the hydrocarbon stream B to a thermal crackerfurnace comprising cracking coil(s); (d) performing a thermal crackingoperation in the presence of steam to obtain a cracked hydrocarbonstream D; (e) supplying the cracked hydrocarbon stream D to a separationunit; and (f) performing a separation operation in the separation unitto obtain a product stream E comprising propylene; wherein in step (d):the coil outlet temperature is ≥800 and ≤850° C.; and the weight ratioof steam to composition C is >0.3 and <0.8.
 14. Process according toclaim 13, wherein the hydrocarbon stream A has an initial boiling pointas determined in accordance with ASTM D86 (2012) of >25° C.; a finalboiling point as determined in accordance with ASTM D86 (2012) of <350°C.; an atomic chlorine content of <10 ppm by weight as determined inaccordance with ASTM UOP 779-08; an atomic nitrogen content of <100 ppmby weight as determined in accordance with ASTM D4629 (2017); and/or abromine number of <10 as determined in accordance with ASTM D1159-07(2012); and or a total sulfur content of <500 ppm as determined inaccordance with ASTM D5453 (2012).
 15. Process according to claim 13wherein in step (c), the feed C consists of the hydrocarbon stream A orwherein the feed C comprises ≥5.0 and ≤90.0 wt %, of hydrocarbon streamA, with regard to the total weight of feed C.